An investigation of the influence of the graphene layers number on the performance of surface plasmon resonance biosensors with various thicknesses of silver

A well-recognized transfer-matrix method has been adopted in modeling an optical fiber-based SPR biosensor. The proposed configuration consists of an optical fiber modified by replacing the cladding with a thin layer of silver-coated graphene layers. The effective area of the biosensor is represented by (fiber core/Ag/G/biomolecules) which are in contact with the biomolecules to be analyzed. The design parameters (i.e., the thickness of Ag and graphene layers) of the proposed model were optimized to improve the sensor performance by enhancing (sensitivity, accuracy, and figure of merit). The best sensitivity improvement was achieved using five layers of graphene and 60 nm of silver, with a good sensitivity improvement value and a low resolution and figure of merit. Graphene can protect silver from oxidation and also help in biomedical sensing thanks to the similarity of some of its properties with biomolecules.